It is well-known that an aromatic primary amine color developing agent oxidized by exposed silver halide used as an oxidizing agent, reacts with a coupler to prepare indophenol, indoaniline, indamine, azomethine, phenoxazine, phenazine, and analogous dyes, whereby a color image is formed.
Of them, an acylacetoamide coupler represented by a benzoyl acetanilide coupler and pivaloyl acetanilide coupler is generally used for forming a yellow color image.
In general, benzoyl acetoanilide couplers have excellent characteristics in that high coupling activity with the aromatic primary amine developing agent on development is high and in that the yellow dye produced has a large molecular extinction coefficient. However, they have the defect that they provide a low fastness of a color image on storage in the dark. While pivaloyl acetamide type couplers have an excellent color image fastness, they have a low coupling reactivity on development and a small molecular extinction coefficient. Therefore obtaining a sufficient color image density requires the use of more coupler, which provides a disadvantage in terms of either image quality or cost.
Thus, the development of a yellow coupler having a high color development (a high coupling activity of a coupler and a high molecular extinction coefficient of a formed dye) and an excellent dye image fastness is attempted as described in, for example, European Patent EP 0 447 969 A1.
While the yellow coupler described in European Patent EP 0 447 969 A1 improves color development and dye image fastness on storage in the dark, color image fastness on light irradiation is deteriorated and therefore an improvement therein has been required.
Meanwhile, recent improvements in operability and requirements of general users have affirmatively promoted low replenishment of the developing solution and rapid processing. A method in which the pH of the developing solution and the processing temperature are increased has been tried as a means to solve this problem. However, there is involved in this method the problem that photographic performance is changed to a large extent during continuous processing and the stability of the developing solution is deteriorated. Therefore it is not suitable for practical use. Another method disclosed in EP 410 450 A2 comprises processing with a developing solution containing a specific developing agent to achieve rapid processing.
However, the above patent discloses that maximum density (Dmax) and sensitivity are lowered with a light-sensitive material containing silver halide having a low silver chloride content (80 mole % or less) even if one of the color developing agents described in this patent is used, and this can not be improved even by prolonging the developing time. Thus, it is impossible to shorten the processing time by a developing agent in a color negative light-sensitive material containing 60 mole % or more of conventional silver bromide.